1. Field of the Invention
The invention encompasses a new adhesive composition and also sheets produced from it, for producing laminates, more particularly for bonding plastic with glass components, a method for producing such laminates, and the laminates produced accordingly.
2. Description of the Background Art
Transparent laminated sheets of glass and plastic are already long-established. There are numerous applications for transparent laminated systems of glass and plastic.
Glass-polymer laminate systems are used, for example, for safety glazing systems in cars, where three-dimensionally curved laminated windows are employed. Examples are given in FR2856951A1 of windows with injection surrounds, and in EP617078B1 of adhesion-regulating and adhesion-reducing systems for more effective splinter binding. An aim with this application is for effective safety at minimum weight. In WO2007080186A1 the laminate claimed is between two preformed, especially thermally pretreated windows with a thermoplastic interlayer, with a description being given of PVB, for example. The window system is claimed specifically for car windows. The thermoplastic interlayer (adhesive layer) is not described in more detail, and no impact strength treatment is mentioned.
WO2001051279A2 describes, by pressing under pressure and temperature, a laminate of glass/adhesive resin/thermoplastic interlayer/adhesive resin/glass particularly for car windscreens.
FR2925483A1 describes a glass-polymer laminate with an internal crosslinked adhesive acrylic resin layer and with a polymer layer of PVB. DE10118617A1 similarly describes the lamination of two glass layers with an acrylic casting resin which, following application to the glass surface, is polymerized and also exhibits adhesion to electrochromic layers. DE2929491A1 (priority 20 Jul. 1979) claims a translucent safety glass comprising two outer glass plates with a central acrylic plate, and uses a flowable, reactive acrylate which is elastic after curing. The soft and tough interlayer is able to absorb some of the impact forces and distribute them over a relatively large area. The additional use of plasticizer acrylates is described. The central acrylate plate, with high impact strength, consists of polymethyl methacrylate (PMMA) and has an acrylic elastomer content of around 20%. Statements concerning a change in transmission as a consequence of temperature change are absent.
Moreover, WO2005058596A1 describes a glass-polymer laminate not only for car windows but also for laminates for architectural applications, consisting of the direct lamination of glass with a polymeric interlayer. This interlayer is based on ethylene-(meth)acrylic acid copolymers.
WO2005005123A1 describes a glass-film laminate in which the adhesion is increased by means of a film which is specially structured, by embossing, and which has increased roughness. Also claimed, in AU2005200410A1, is the structuring of a thermoplastic interlayer for glass laminates, based on plasticized polyvinyl acetal, for preventing the development of a moiré phenomenon. WO2011080464A1 and FR2948357A1 each describe a laminate of a mineral glass with an organic glass via an interlayer, which in order to prevent optical disruptions has a certain thickness variance. PMMA is among the organic glass described. For the thermoplastic interlayer (adhesive layer), descriptions are given of PVB, PU, etc.
US20050202198A1 claims the procedure for producing a laminate of glass, thermoplastic adhesive sheet, thermoplastic polymer plate, a further thermoplastic adhesive sheet, and a second glass pane. The adhesive sheet is based on thermoplastic polyurethane, which is provided with PE protective films. The central thermoplastic plate material used is polycarbonate (PC).
Laminated windows additionally play an important part in protection against shooting and explosions. Shot resistance is achieved by laminating a plurality of layers of thick glass panes, with soft or ductile polymer layers between them. Depending on the degree of shot resistance desired, the systems needed vary in thickness. Bulletproof windows are employed in cars, in armoured vehicles for military use, or in the protection of sensitive buildings. Examples are given in U.S. Pat. No. 5,506,051A of laminated windows with flexible interlayers, and in WO9962707A1 of a laminated glass with an external thick-layer coating.
As well as these applications, the use of laminated glazing is also specified for fire protection glazings, as for example via an intumescent layer in DE202010008723U1, for thin-layer photovoltaic modules in DE102009025972A1, for safety laminates and solar modules with a polyolefin-based outer layer for improving the abrasion resistance in US20100108143A1 and US20100108127A1, and for special glazing systems with further finishes and properties, such as anti-breaking glazing systems in DE 19526912 A1, for example, through use of layered sheets, and in EP2199075A1, through ethylene-methacrylic acid copolymers, for surface lamination.
Also known are special windows such as, for example, lead glazing systems in EP259529B1, glass-plastic laminates with electrically conductive layers and a gas-filled zone in WO2010063729A1 and US20040022970A1, TV front screens in U.S. Pat. No. 3,867,222A, and also heat management, and stormproof or hurricane-resistant glazing systems for buildings, with special silicate glasses having extreme load-bearing properties. WO2004089617A1, WO2004089618A1, WO2004089619A1 and WO2004011755A1 claim direct adhesion to glass using ethylene-methacrylic acid copolymers. Likewise noteworthy here is US20060201078A1, which claims a glass laminate of glass and a thermoplastic, high-impact polymer layer, which by virtue of a special construction allows the realization of extensive glass laminate areas without further frame reinforcement.
DE10045006C1 describes a casting resin which comprises reactive acrylate- or methacrylate-functional oligomers. Statements concerning behaviour after temperature cycling stress are absent.
WO2010010156A1 claims a safety glazing system based on glass windows and thermoplastic interlayers with improved acoustics. All that is said about the thermoplastics is that within the overall laminated system their acoustics are better than with PVB. There is no further description of the thermoplastics.
DE660634C specifies a method for producing a splinterproof laminated glass with high weathering stability, by joining the glass windows using a soft polyacrylate interlayer. The polyacrylate interlayer can be produced by laminating a film produced from the monomers, or by polymerizing the monomers between the glass plates. DE2524729A1 describes a safety glass composed of mineral glass and polycarbonate with soft interlayers. WO03078485A1 describes a laminated glass made up of comparatively thin outer glass windows and PMMA interlayer with adhesion-promoting components based on silane.
In the adhesive bonding of glass and PMMA, stresses occur because of the differences in thermal expansion coefficient between glass and PMMA, and these stresses, in the event of sharp temperature differences, can lead to warping, delamination or destructive rupture of the laminated windows. If, for example, thin glass is joined using soft adhesives, there is the problem that the striking of a hard object against the hard silicate glass may easily entail damage. If a hard composite material is used as in WO03078485A1, the laminate plate does remain undamaged on striking, in spite of thin glass, but the laminated system is unable to accommodate the stresses between the glass sides during climatic change or in the event of large temperature differences.
As demonstrated by the multiplicity of patent applications, a large demand exists for composite glass systems having an expanded spectrum of properties, with weight in particular playing a prominent part. There have already been numerous attempts to produce lightweight and long-lived glass-polymer laminates with further properties, and yet to date no success has been achieved in producing long-lived glass-polymer laminates with low weight, with heat and noise insulation properties and with very good optical properties, in a cost-effective procedure. Consequently there continues to be a need for new materials, especially adhesives for producing laminates, more particularly those of glass and plastic.